Which two statements are true about traffic shaping and traffic policing？（） A: both traffic shaping and traffic policing cause retransmissions of connection-oriented protocols such as TCP B: both traffic shaping and traffic policing support the marking and re-marking of traffic C: the effects of traffic shaping and traffic policing when configured on a router are applied to outgoing traffic D: traffic shaping queues excess traffic whereas traffic policing discards excess traffic E: traffic shaping allows the traffic to exceed the bit rate whereas traffic policing prevents the traffic from exceeding the bit rate

下面全都是后鼻韵母的是哪一组？: ang、eng、ing、ong、ian|ang、eng、iou、ong、ueng|iang、ong、ing、ueng、iong|iong、eng、ian、ong、uang

The following are not road traffic signals ( ). A: traffic light B: traffic sign C: traffic information board D: traffic police command

韵母eng属于合口呼。（）

下面全都是后鼻韵母的是哪一组? A: ang、eng、ing、ong、ian B: iang、ong、ing、ueng、iong C: ang、eng、iou、ong、ueng D: iong、eng、ian、ong、uang

Children should be taught to read __________ A: traffic signs B: traffic island C: traffic jam D: traffic police

以下选项中的音素可以充当尾音的是（ ） A: i a ü B: i eng ü C: i u o D: n eng a

A traffic conflict is equivalent to a traffic accident.( )

They didn’t catch the train hecause of ( ) A: some heavy traffic B: any heavy traffic C: a heavy traffic D: heavy traffic

“空中交通管制”可以表达为"_____". A: air traffic warning B: air traffic control C: traffic control D: air traffic clearance